Doctoral Degrees (Industrial Engineering)
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Browsing Doctoral Degrees (Industrial Engineering) by Subject "Arid regions"
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- ItemSustainable future CSP fleet deployment in South Africa: A hydrological approach to strategic management(Stellenbosch : Stellenbosch University, 2019-12) Duvenhage, Dries Frank; Brent, Alan C.; Stafford, W. H. L.; Grobbelaar, Sara; Stellenbosch University. Faculty of Engineering. Dept. of Industrial Engineering.ENGLISH ABSTRACT: The global growth in renewable energy, as a means to mitigate climate change, has seen the large-scale deployment of solar photovoltaics (PV) and wind in the electricity generation mix. However, this presents several challenges; primarily that both wind and PV are unpredictable and therefore cannot supply reliable electricity. This necessitates energy storage or the other, more flexible electricity generators to meet the shortfall. Concentrating solar power (CSP) can supply this shortfall in electricity through the concentration of solar irradiation and thermal storage of this heat. This thermal process requires cooling, best achieved with a finite resource, namely water. Paradoxically, CSP is ideally suited to areas of high solar irradiation that are characteristically arid with low and variable water availability. However, the need for water, mainly as a source of cooling, is often neglected in the planning and development of CSP at a national scale, with few studies that explicitly assess and quantify these hydrological constraints. This study aims to fill this research gap by improving our understanding of the constraints imposed by water resources on CSP development in arid regions, using South Africa as a case study. A systematic approach was used to model the hydrological constraints to CSP plants’ operation and its wide-spread deployment. To determine to what extent CSP might play a role in supplying electricity to the South African grid, a review of future energy mix plans was performed. Although the theoretical potential of CSP based on the solar resource and suitable land is around 12,000 TWh (for the most efficient commercial CSP technologies), the current plans limit this potential considerably to between only 1.87 TWh and 142 TWh. Furthermore, these allocated capacities to CSP in the South African electricity supply are well below the limitations imposed by water resources, especially if dry-cooled plants are used. CSP performance varies according to design and location, since meteorological conditions vary spatially and temporally. A high-level efficiency model (HLEM) was developed to quantify this variability in South Africa. It uses validated equations and assumptions from literature with CSP energy transfer efficiencies to determine monthly performance in terms of net electricity generation, water consumption factor and total volume of water consumption. Parabolic Trough and Central Receiver CSP plants were modelled with either wet or dry cooling and the CSP performance analysed at thousands of suitable locations in South Africa. To assess water availability for CSP deployment at these locations, publicly available hydrological data for river flows, dam storage levels and groundwater reserves were used. The water demand from the four CSP-cooling configurations was then measured against the monthly available water per quaternary catchment area. The hydrological limitations were calculated for each configuration, and it was found that, depending on the CSP-cooling configuration, water availability will reduce the theoretical potential for CSP deployment to between 1 - 5% thereof (from 12,000 TWh to 120 – 566 TWh). These results provide guidelines for policy and planning of CSP deployment in South Africa, to ensure the sustainable management of water resources.